In recent years, the demand for the lower fuel consumption of automobiles has become increasingly severe in connection with the social need for energy saving. In order to respond to such a demand, a further reduction in the rolling resistance of tire has been requested. As the method for reducing the rolling resistance of tire, the optimization of tire structure has been studied; however, it is generally conducted to use, as the rubber composition for tire, a material low in heat build-up.
In order to obtain such a rubber composition low in heat build-up, a number of technical studies have hitherto been made to develop a modified rubber for the rubber composition which contains silica and carbon black as a filler. There was proposed, for example, a method for producing a polymer, which comprises subjecting a conjugated diolefin or a conjugated diolefin and an aromatic vinyl compound to anionic polymerization in a hydrocarbon solvent by using, as an initiator, at least one compound selected from the groups consisting of organic alkali metals and organic alkaline earth metals, to obtain a polymer and then reacting the terminal of the polymer with a particular amino group-containing alkoxysilane compound (see, for example, Patent Literature 1).
Patent Literature 1: WO 03/029299 Pamphlet